diff --git a/include/wx/msw/window.h b/include/wx/msw/window.h
index b5058d57da..03e752e92f 100644
--- a/include/wx/msw/window.h
+++ b/include/wx/msw/window.h
@@ -50,6 +50,7 @@ class WXDLLEXPORT wxWindowMSW : public wxWindowBase
     friend class wxSpinCtrl;
     friend class wxSlider;
     friend class wxRadioBox;
+    friend class wxWindowMSW;
 public:
     wxWindowMSW() { Init(); }